37 lines
1.2 KiB
GLSL
37 lines
1.2 KiB
GLSL
precision mediump float;
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varying vec4 v_color;
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varying vec2 v_texcoord;
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uniform bool is_top_left;
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uniform bool is_top_right;
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uniform bool is_bottom_left;
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uniform bool is_bottom_right;
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uniform vec2 position;
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uniform float radius;
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uniform vec2 half_size;
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uniform float half_thickness;
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float roundedBoxSDF(vec2 center, vec2 size, float radius) {
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return length(max(abs(center) - size + radius, 0.0)) - radius;
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}
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void main() {
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vec2 center = gl_FragCoord.xy - position - half_size;
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float distance = roundedBoxSDF(center, half_size - half_thickness, radius + half_thickness);
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float smoothedAlphaOuter = 1.0 - smoothstep(-1.0, 1.0, distance - half_thickness);
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// Create an inner circle that isn't as anti-aliased as the outer ring
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float smoothedAlphaInner = 1.0 - smoothstep(-1.0, 0.5, distance + half_thickness);
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gl_FragColor = mix(vec4(0), v_color, smoothedAlphaOuter - smoothedAlphaInner);
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if (is_top_left && (center.y > 0.0 || center.x > 0.0)) {
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discard;
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} else if (is_top_right && (center.y > 0.0 || center.x < 0.0)) {
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discard;
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} else if (is_bottom_left && (center.y < 0.0 || center.x > 0.0)) {
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discard;
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} else if (is_bottom_right && (center.y < 0.0 || center.x < 0.0)) {
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discard;
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}
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}
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